Polymer surface structures, which govern a variety of material properties such as wetting, adsorption, catalyzing, friction, adhesion, and light absorption/refraction, have been highly attractive to the scientific community. The properties of polymer surface depend on their chemical compositions and surface microstructures as well as their synergy. Recent advances in polymer microstructure have led to the emergence of a variety of applications, including super-hydrophobic/self-cleaning materials, photonic crystal, microfluidics (Chen, J. Micromech. Microeng., 2015, 25: 0035001).
The representative published patents about super-hydrophobic/self-cleaning surface include Chinese patents No. CN104475309A, No. CN104449357A and U.S. Pat. No. 9,040,145. Chinese patent No. CN104475309A has disclosed a method for preparing super-hydrophobic surface, comprising: step 1: selecting a super-hydrophobic material as the substrate layer; step 2: smearing a silicone rubber precursor onto the substrate and then curing silicone rubber; step 3: preparing nanoparticle suspensions and smearing the nanoparticle suspensions onto the cured silicone rubber, after solvent volatilizing, forming the nanoparticle thin film above the silicone rubber; step 4: after ultraviolet light or heat treatment, a layered super-hydrophobic material is obtained.
The published patents about photonic crystals include No. CN104044342A, U.S. Pat. No. 8,541,150, etc. For example, Chinese patent application No. CN104044342A disclosed photonic crystal pattern through an ink-jet printing method. The photonic crystal pattern is formed as an opal structure through the method of ink-jet printing method.
The present technologies for preparation microstructures include: photolithography (U.S. Pat. Nos. 4,081,314, 4,049,347), etching method (Namba, Appl.phys.lett., 1982,40:374), compression molding (U.S. Pat. Nos. 8,333,583, 6,482,742), micro molding (Whitesides, Science, 1996, 273:347). Each method has its pros and cons. It is difficult for the methods mentioned above to prepare complex 3D polymer objects with surface micro-nanostructures. In the case of a polymer surface with small thickness, the shortcomings of the above methods become more obvious.